Out of that lot, The 911 GT3 is great, but the basic Carrera 4 is still a good car, and much cheeper. The RX8 is certainly entertaining, and refreshingly different, but top on my list would be the TVR Cerbera 4.5. This is Ferrari 550 performance (and if the truch is known, better quality) for a third of the price!
The 206 GTi180 is sharp, as is the Mini Coopper S. The Lotue Elise and Vauxhall VX220 Turbo are others that I feel should really be on the list.